Convert "middleware not registered" warning into a full error

packages/toolkit/src/query/core/buildInitiate.ts

@@ -300,9 +300,9 @@ export function buildInitiate({
         ;(middlewareWarning as any).triggered = true
       }
       if (registered === false) {
-        console.warn(
+        throw new Error(
           `Warning: Middleware for RTK-Query API at reducerPath "${api.reducerPath}" has not been added to the store.
-Features like automatic cache collection, automatic refetching etc. will not be available.`
+You must add the middleware for RTK-Query to function correctly!`
         )
       }
     }

packages/toolkit/src/query/react/buildHooks.ts

@@ -716,6 +716,15 @@ export function buildHooks<Definitions extends EndpointDefinitions>({
           })
         )
 
+        if (process.env.NODE_ENV !== 'production') {
+          if (typeof returnedValue !== 'boolean') {
+            throw new Error(
+              `Warning: Middleware for RTK-Query API at reducerPath "${api.reducerPath}" has not been added to the store.
+    You must add the middleware for RTK-Query to function correctly!`
+            )
+          }
+        }
+
         currentRenderHasSubscription = !!returnedValue
       }
 

packages/toolkit/src/query/tests/buildHooks.test.tsx

@@ -18,13 +18,18 @@ import {
   expectExactType,
   expectType,
   setupApiStore,
+  withProvider,
   useRenderCounter,
   waitMs,
 } from './helpers'
 import { server } from './mocks/server'
 import type { AnyAction } from 'redux'
 import type { SubscriptionOptions } from '@reduxjs/toolkit/dist/query/core/apiState'
-import { createListenerMiddleware, SerializedError } from '@reduxjs/toolkit'
+import {
+  createListenerMiddleware,
+  SerializedError,
+  configureStore,
+} from '@reduxjs/toolkit'
 import { renderHook } from '@testing-library/react'
 import { delay } from '../../utils'
 
@@ -651,6 +656,39 @@ describe('hooks tests', () => {
       const res = await resPromise
       expect(res.data!.amount).toBeGreaterThan(originalAmount)
     })
+
+    describe('Hook middleware requirements', () => {
+      let mock: jest.SpyInstance
+
+      beforeEach(() => {
+        mock = jest.spyOn(console, 'error').mockImplementation(() => {})
+      })
+
+      afterEach(() => {
+        mock.mockReset()
+      })
+
+      test('Throws error if middleware is not added to the store', async () => {
+        const store = configureStore({
+          reducer: {
+            [api.reducerPath]: api.reducer,
+          },
+        })
+
+        const doRender = () => {
+          const { result } = renderHook(
+            () => api.endpoints.getIncrementedAmount.useQuery(),
+            {
+              wrapper: withProvider(store),
+            }
+          )
+        }
+
+        expect(doRender).toThrowError(
+          /Warning: Middleware for RTK-Query API at reducerPath "api" has not been added to the store/
+        )
+      })
+    })
   })
 
   describe('useLazyQuery', () => {

packages/toolkit/src/query/tests/devWarnings.test.tsx

@@ -52,6 +52,9 @@ beforeEach(() => {
   ;[api1, api1_2, api2] = createApis()
 })
 
+const reMatchMissingMiddlewareError =
+  /Warning: Middleware for RTK-Query API at reducerPath "api" has not been added to the store/
+
 describe('missing middleware', () => {
   test.each([
     ['development', true],
@@ -61,13 +64,14 @@ describe('missing middleware', () => {
     const store = configureStore({
       reducer: { [api1.reducerPath]: api1.reducer },
     })
-    store.dispatch(api1.endpoints.q1.initiate(undefined))
-    expect(getLog().log).toBe(
-      shouldWarn
-        ? `Warning: Middleware for RTK-Query API at reducerPath "api" has not been added to the store.
-Features like automatic cache collection, automatic refetching etc. will not be available.`
-        : ''
-    )
+    const doDispatch = () => {
+      store.dispatch(api1.endpoints.q1.initiate(undefined))
+    }
+    if (shouldWarn) {
+      expect(doDispatch).toThrowError(reMatchMissingMiddlewareError)
+    } else {
+      expect(doDispatch).not.toThrowError()
+    }
   })
 
   test('does not warn if middleware is not missing', () => {
@@ -83,11 +87,12 @@ Features like automatic cache collection, automatic refetching etc. will not be
     const store = configureStore({
       reducer: { [api1.reducerPath]: api1.reducer },
     })
-    store.dispatch(api1.endpoints.q1.initiate(undefined))
-    store.dispatch(api1.endpoints.q1.initiate(undefined))
-    expect(getLog().log)
-      .toBe(`Warning: Middleware for RTK-Query API at reducerPath "api" has not been added to the store.
-Features like automatic cache collection, automatic refetching etc. will not be available.`)
+    const doDispatch = () => {
+      store.dispatch(api1.endpoints.q1.initiate(undefined))
+    }
+
+    expect(doDispatch).toThrowError(reMatchMissingMiddlewareError)
+    expect(doDispatch).not.toThrowError()
   })
 
   test('warns multiple times for multiple apis', () => {
@@ -97,13 +102,16 @@ Features like automatic cache collection, automatic refetching etc. will not be
         [api2.reducerPath]: api2.reducer,
       },
     })
-    store.dispatch(api1.endpoints.q1.initiate(undefined))
-    store.dispatch(api2.endpoints.q1.initiate(undefined))
-    expect(getLog().log)
-      .toBe(`Warning: Middleware for RTK-Query API at reducerPath "api" has not been added to the store.
-Features like automatic cache collection, automatic refetching etc. will not be available.
-Warning: Middleware for RTK-Query API at reducerPath "api2" has not been added to the store.
-Features like automatic cache collection, automatic refetching etc. will not be available.`)
+    const doDispatch1 = () => {
+      store.dispatch(api1.endpoints.q1.initiate(undefined))
+    }
+    const doDispatch2 = () => {
+      store.dispatch(api2.endpoints.q1.initiate(undefined))
+    }
+    expect(doDispatch1).toThrowError(reMatchMissingMiddlewareError)
+    expect(doDispatch2).toThrowError(
+      /Warning: Middleware for RTK-Query API at reducerPath "api2" has not been added to the store/
+    )
   })
 })